In a connection-oriented communication network constructed as a telephone network, a multiplicity of connections, which are mainly set up for implementing the services offered, exist at any given time. In most cases, the services are used in a regulated manner, their use is also designated as call, via additional control mechanisms. These are constructed differently depending on the type of service. They can be implemented as central controller, as decentralized controller or as interconnected controllers.
The standard service of a telephone network, a call between two subscribers, is in most cases implemented via a connection. The control of this service is usually designed as distributed control; i.e., it is performed by control entities which are distributed over the switching facilities of the communication network. This type of control is also called call processing in the profession. Call processing performs the actions intended for the connection (e.g., connection set-up and release) and possibly also the translation of the protocols of supplementary services (e.g., calling party identification). For this purpose, an exchange of parameters, among other things, is also performed between the control entities, where the time of the exchange and the type of parameters are described in protocols specified for the respective actions and services. This exchange is only provided between those control entities which are associated with the same connection.
Complex services such as, for example, conferences between a number of subscribers, frequently require correspondingly extended control mechanisms. A model for implementing these additional mechanisms consists in the expansion of the telephone networks into so-called intelligent networks (IN). In this arrangement, the switching facilities, now also called service switching points (SSP), are supplemented by at least one service control point (SCP) which controls at least the parts of the complex services going beyond the standard services already provided by the switching facilities. This model is thus an interconnection of controllers. A control corresponding to this model is also called call party handling (CPH) in the profession. Depending on the type of service to be controlled, different service-specific controls are implemented in this model.
A service-specific control is described in International ITU Standard Q.1224 “Distributed Functional Plane for Intelligent Network Capability Set 2”, 09/97, and is called a Connection View Model. The basis for this model is a service which is implemented at least from time to time by two isolated part-connections, also called call segments. These call segments are usually implemented as standard services and, in consequence, controlled by completely separate controllers; i.e., each call segment is controlled by an associated call processing function. Such call processing associated with a call segment will be called call segment processing in the further text.
In addition, this model enables                1. a number of connections (also called call segments, if necessary, in the text which follows) to be connected together and separated to form a uniform end-to-end connection, also called “call”,        2. announcements and tones to be applied during the setting-up and/or the existence of the connections, and        3. connections to be set up which are initiated by the service control point (SCP).        
The connection view model will be explained in the text which follows, using the Secure Answer service as an example. In this service, an announcement that the called subscriber is currently entering an identification in order to authenticate himself/herself is transmitted to the calling subscriber 318 during the setting-up of a call. After the successful authentication, the call segments are connected together. To the subscribers, the call appears as a unit even though it is controlled by a number of separate call segment controllers at least from time to time since the following two call segments are already set up during the setting-up:                1. between the calling subscriber and the entity transmitting the announcement, which is controlled by a first call segment controller, and        2. between the called subscriber and the entity carrying out the authentication, which is associated with a second call segment controller.        
According to this model, the call segment controllers involved are usually coordinated by a coordination function provided in the SCP.
If, however, a call is initially set up with two segments and then connected together, many of the supplementary services cannot be used in this approach to a solution since no transmission of parameters between connection controllers associated with different connections is provided. The following table contains a selection of services affected and names the originating parameters for these in each case.
ServiceRequired parameterCalling Line IdentificationCalling Party Number(CLIP)Malicious Call IdentificationCalling Party Number(MCID)Connected Line Identification PresentationConnected Line Identity(COLP)Request IndicationConnected NumberCall Forwarding (CF)Redirecting NumberOriginal Called Party NumberRedirection InformationClosed User Group (CUG)Closed User Group IndicatorCall Hold (HOLD)HoldRetrieveTerminal Portability (TP)SuspendResumeGeneric ServicesGeneric NotificationsCall Waiting (CW)User-to-UserInformation(UUI)User-to-User Signaling (UUS)CCBS possible indicatorCompletion of calls to busyCCNR possible indicatorsubscriber (CCBS)Completion of calls on no reply (CCNR)Conferences (*)Backward ConferenceTreatment Indicator(*) the information for dealing with conferences may be received by other SCPs in a correspondingly configured intelligent network.
In International ITU Standard Q.1228, “Interface Recommendation for intelligent network Capability Set 2”, 09/97, an Intelligent Network Application Protocol (INAP) is described, with the aid of which some of the set parameters can be transferred between the call segment controllers.
In this arrangement, the transfer of the parameters between the call segment controllers is always performed via the SCP and is provided for the following services or parameters, respectively:
ServiceRequired parameterCalling Line identificationCalling Party Number(CLIP)Malicious Call Identification (MCID)Call Forwarding (CF)Redirecting NumberOriginal Called Party NumberRedirection Information
In this arrangement, the transfer of parameters is specified separately for each parameter in the INAP. Thus, the INAP must be adapted for each additional parameter which is introduced in the telephone network if it is intended to exchange the parameter between call segment controllers. At present, the INAP does not provide any support for the following services; i.e., the parameters cannot be transferred in at least one direction and the associated services thus cannot be used:
ServiceRequired parameterConnected Line IdentificationConnected Line Identity RequestPresentation (COLP)IndicatorConnected NumberClosed User Group (CUG)Closed User Group IndicatorCall Hold (HOLD)HoldRetrieveTerminal Portability (TP)SuspendResumeGeneric ServicesGeneric NotificationsCall Waiting (CW)User-to-User Information (UUI)User-to-User Signaling (UUS)CCBS possible indicatorCompletion of calls to busy subscriberCCNR possible indicator(CCBS)Completion of calls on no reply(CCNR)ConferencesBackward Conference TreatmentIndicator
The present invention is, therefore, directed toward improving the method for transferring parameters between connection controllers.